Dynamic hysteresis in Finemet thin films

We performed a series of dynamic hysteresis measurements on three series of Finemet films with composition Fe$_{73.5}$Cu$_1$Nb$_3$Si$_13.5$B$_9$, using both the longitudinal magneto-optical Kerr effect (MOKE) and the inductive fluxometric method. The MOKE dynamic hysteresis loops show a more marked variability with the frequency than the inductive ones, while both measurements show a similar dependence on the square root of frequency. We analyze these results in the frame of a simple domain wall depinning model, which accounts for the general behavior of the data.